1. Field of the Invention
The present invention relates to an image processing method, an image processing apparatus, and a generating method for printing an image on a printing medium by executing one of a plurality of printing modes.
2. Description of the Related Art
Recently, printing apparatuses (printing apparatuses) represented by ink jet printers are requested to cope with a plurality of types of printing media. As printing materials, ink of light cyan (PC), ink of light magenta (PM), ink of gray (Gy), and the like are used in addition to ink of cyan (C), magenta (M), yellow (Y), and black (K). In addition, a printing system is known in which ink of red (R), green (G), blue (B), and the like is added so as to enlarge a color gamut. Such a color printing apparatus is connected to a personal computer (PC). Then, by processing printing data produced by the PC using a printer driver or a raster image processor (RIP) software solution, the printing data is printed on a printing medium such as paper. In image processing performed in a printing system using a PC and a printing apparatus, generally, after a color adjusting process, a color matching (color correction) process, a color separation process, and a halftoning process are performed, ink is ejected onto a printing medium, whereby an image is printed. Image data output from the PC to the printing apparatus is image data of an RGB signal in a case where a printer driver is used, and is image data of a CMYK signal in a case where a RIP software solution is used.
In such a printing system, color separation information that is appropriate for each printing medium is prepared in the color separation process. In addition, in the color matching process, color matching information is prepared for each printing purpose (for example, “photograph-like”, “vividness preference”, “color difference preference”, and the like). Such information is used while being stored and managed as a color parameter of a maker-specific format and in an ICC color profile format.
In addition, in a printing system using an ink jet printer, a plurality of printing modes according to the purposes is prepared. A printing mode is a printing condition according to the purpose of printing an image, and, by executing such a printing mode, an image is printed on a printing medium. For example, as printing modes, there are an image quality priority mode in which a high-quality image is printed, a speed preference mode in which printing is performed at high speed, and the like. Generally, “fine” that is the image quality priority mode, “fast” that is the speed preference mode, “standard” that is an intermediate mode therebetween, and the like can be selected in a stepped manner and can be set in an UI display. Here, the image quality priority mode is realized by controlling printing conditions for, compared to the standard mode, setting the printing resolution to relatively high resolution (1200×2400 dpi), increasing the number of scans in multi-pass printing, decreasing the carriage speed of a printing head ejecting ink, and the like. On the other hand, the speed preference mode is realized by controlling printing conditions for, compared to the standard mode, setting the printing resolution to relatively low resolution (1200×1200 dpi), decreasing the number of scans in multi-pass printing, increasing the carriage speed of the printing head, and the like.
When the printing conditions are set as described above, a reproducible color gamut is determined in accordance with each printing medium. For example, in the image quality priority mode, a maximum value (hereinafter, referred to as a maximum ink applying amount) of the amount of ink applied to a unit area of a printing medium is larger than that in the speed preference mode, and accordingly, it is possible to reproduce a color gamut broader than that of the speed preference mode. In Japanese Patent Application Laid-Open No. 9-186898, it is disclosed that a color separation table corresponding to each printing mode is generated in consideration of the output characters of each printing mode such that the reproducible color gamut can be maximally used. However, in a case where a color separation table that is optimal for each printing mode is generated as in Japanese Patent Application Laid-Open No. 9-186898, there is a case where images of mutually different colors are printed in accordance with printing modes even for the same input image signal.
FIG. 13A illustrates a color separation table corresponding to a printing mode A having a relatively broad color gamut and a color separation table corresponding to a printing mode B having a relatively narrow color gamut. FIG. 13B illustrates the color gamuts of the printing modes A and B. In a case where images are printed by inputting the same image signals (RGB values) to such color separation tables and separating the image signals for each color, a color reproduction value (L*a*b* value) of the image printed in the printing mode A is a point 121, and a color reproduction value of the image printed in the printing mode B is a point 122. In other words, in order to print images of the same color for the same input image signals regardless of the printing modes, a color matching table corresponding to each color separation table needs to be prepared.
In addition, the color separation tables need to be different also in accordance with the printing purposes such as “photograph-like”, “vividness preference”, and “color difference preference” and the type of printing medium. Accordingly, in a printing system in which the printing purpose and the printing medium can be selected from among a plurality of printing purposes and a plurality of printing media, color separation tables that is color separation information corresponding to the numbers thereof need to be prepared. For example, in a printing system corresponding to three types of printing modes, three types of printing purposes, and three types of printing media, color separation tables of 3×3×3=27 types are necessary. In addition, a color matching table corresponding to each color separation table needs to be prepared.
The preparation of color matching tables corresponding to the number of the types of printing media, printing modes, and printing purposes as described above leads not only to an increase in the number of design processes and capacity enlargement of a memory storing such information but also to a high processing load at the time of printing an image. Further in a case where a user generates a profile that is a color matching table, the profile needs to be generated for each printing mode, whereby the load is high. At this time, an ICC profile that is color matching information needs to be designated for each printing mode, and thus, there is a problem in that the convenience at the time of printing an image is degraded.
An embodiment of the present invention is in view of such problems and provides an image processing method and an image processing apparatus capable of lowering the processing load and suppressing capacity enlargement of the memory while utilizing the color gamut for each printing mode to a maximum extent.